This speaks of the enemy army conquering the land of Ammon and taking possession of the land and everything in it as if the enemy were taking the people of Ammon as their possession. It is not implied here that the enemy took the people of Ammon as slaves. Alternate translation: "I will cause an army from a land that is east of you to come and conquer you" (See: [[rc://en/ta/man/translate/figs-metaphor]])
It may be helpful to specify the source of the fruit and milk. Alternate translation: "They will eat the fruit from your trees and drink the milk from your cattle" (See: [[rc://en/ta/man/translate/figs-explicit]])